Device with sharp and blunt regions for removing occlusions

ABSTRACT

Disclosed herein is a device for disrupting material in a body vessel and a method for making such a device. The device includes a plurality of arms disposed circumferentially about an axis. Each arm includes two blades; one sharper, and one blunter. The sharper blades are all oriented in the same direction, clockwise or counterclockwise, such that when the device is rotated in a first direction, the sharper blades engage the material, and in the other, the duller blades engage the material.

BACKGROUND

The present application generally relates to medical devices. Moreparticularly, the present application relates to a device for disruptingmaterial within a body vessel, such as in a venous thrombectomy oratherectomy procedure.

A number of disease states can lead to the full or partial occlusion ofthe lumen of a vessel, such as atherosclerosis leading to the occlusionof an artery, or deep vein thrombosis, leading to occlusion of a vein.There are a number of minimally-invasive procedures and related devicesthat can be used to remove these occlusions, such as atherectomy andthrombectomy. A number of these devices rely on rotating elements tomechanically disrupt the occlusion, with the disrupted material beingsubsequently removed to restore patency to the vessel lumen.

Vascular occlusions are frequently heterogeneous in nature.Atherosclerotic plaques may contain regions with soft, fatty deposits,and other regions with heavy calcification. Venous thrombotic occlusionsmay have regions with acute, soft thrombus and with sub-acutecross-linked fibrotic regions. Currently available medical devicestypically do not allow control of the cutting or disruptive ability ofthe system, other than by changing the speed at which the systemrotates. A system that would allow the physician to more readily varythe disruptive power of the device in response to changing properties ofthe occlusion would facilitate removal while limiting damage to theunderlying blood vessel, minimizing such undesired consequences asvenous valve damage, perforation, endothelium denudation, and the like.

It has been a challenge to develop a rotary tool which is capable ofprocessing material in a body vessel which includes both sharp and dullcutting surfaces.

SUMMARY

In one aspect, the present disclosure provides a medical device fordisrupting material in a body vessel, the medical device comprising: abody comprising a first end and extending to a second end, the bodycomprising an inner surface and an outer surface opposite the innersurface, the body comprising a first tubular portion, a plurality ofarms, and a second tubular portion, the plurality of arms being disposedbetween and connected to the first tubular portion and the secondtubular portion, the first tubular portion comprising the first end andthe body defining a longitudinal axis therethrough; the second tubularportion comprising the second end and disposed about the longitudinalaxis, the second tubular portion being axially displaced from the firsttubular portion; and each of the plurality of arms comprising: an outerface continuous with the outer surface, an inner face continuous withthe inner surface, a first blade, and a second blade; each of the firstblade and the second blade being disposed between the outer face and theinner face, the first blade being sharper than the second blade; andeach of the plurality of arms being arranged such that each first bladeis in the same relative orientation in a circumferential direction.

In another aspect, the present disclosure provides a medical device fordisrupting material in a body vessel, the medical device comprising: abody comprising a first end and extending to a second end, the bodycomprising an inner surface and an outer surface opposite the innersurface, the body comprising a first tubular portion, a plurality ofarms, and a second tubular portion, the plurality of arms being disposedbetween and connected to the first tubular portion and the secondtubular portion, the first tubular portion comprising the first end andthe body defining a longitudinal axis therethrough; the second tubularportion comprising the second end and disposed about the longitudinalaxis, the second tubular portion being axially displaced from the firsttubular portion; and each of the plurality of arms comprising: an outerface continuous with the outer surface, an inner face continuous withthe inner surface, a first faceted blade, and a second blade; each ofthe first faceted blade and the second blade being disposed between theouter face and the inner face, the first blade being sharper than thesecond blade; and each of the plurality of arms being arranged such thateach first faceted blade is in the same relative orientation in acircumferential direction.

In a further aspect, the present disclosure provides a method of makinga medical device for disrupting material in a body vessel, the methodcomprising: making a plurality of first cuts in a tubular body, thetubular body comprising an inner surface and an outer surface andextending from a first end to a second end defining a longitudinal axistherethrough, each first cut originating between the first end and thesecond end and terminating between the first end and the second end;making a plurality of second cuts in the tubular body offset from thefirst cut to define a plurality of arm region between each first cut andits corresponding second cut, each second cut originating between thefirst end and the second end and terminating between the first end andthe second end; displacing a portion of each arm region outward radiallyto define a plurality of arms, each arm comprising a first blade definedby the first cut and having a first sharpness, and a second bladedefined by the second cut and having a second sharpness different thanthe first sharpness, each of the plurality of arms being oriented suchthat each first blade is in the same relative orientation in acircumferential direction, wherein at least one of the first cuts andthe second cuts are made in a plane which does not intersect thelongitudinal axis.

Further objects, features and advantages of this system will becomereadily apparent to persons skilled in the art after a review of thefollowing description, with reference to the drawings and claims thatare appended to and form a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1E are schematic views of cuts made to create a vasculartreatment device constructed in accordance with a prior art method;

FIG. 2 is a perspective view of a series of cuts in a precursor tubemade in accordance with an embodiment of the present disclosure;

FIGS. 3A-3E are schematic views of cuts made to create a vasculartreatment device constructed in accordance with an embodiment of thepresent disclosure;

FIGS. 4A-4E are schematic views of cuts made to create a vasculartreatment device constructed in accordance with a further embodiment ofthe present disclosure;

FIG. 5 is a perspective view of a device constructed in accordance withan embodiment of the present disclosure;

FIG. 5A is a close up view of a blade profile of the device of FIG. 5 ;

FIGS. 6A-6C are schematic views of blade profiles of further embodimentsof the present disclosure;

FIG. 7 is a schematic view of blades cut for a device in accordance withthe principles of another embodiment of the present disclosure;

FIG. 8 is a side view of a cut made in a tube when constructing a devicein accordance with another embodiment of the device disclosed herein;and

FIGS. 9A-9E are views of a cutting scheme and blades in accordance withanother aspect of the present disclosure.

DETAILED DESCRIPTION

The drawings are purely schematic illustrations of various aspects ofthe device and method being described, and are not necessarily to scale,unless expressly stated.

The terms “substantially” or “about” used herein with reference to aquantity includes variations in the recited quantity that are equivalentto the quantity recited, such as an amount that is equivalent to thequantity recited for an intended purpose or function. “Substantially” orderivatives thereof will be understood to mean significantly or in largepart. When used in the context of a numerical value or range set forth,“about” or “substantially” means a variation of ±15%, or less, of thenumerical value. For example, a value differing by ±15%, ±14%, ±10%, or±5%, among others, would satisfy the definition of “about.”

FIGS. 1A-1E are illustrative of a cutting scheme used to make a cuttingtool by a known, prior art method. FIG. 1A shows an end view of a tube10, such as a metal cannula, which has center 12. A cut is made startingalong cut line 14 through the wall of the tube 10 at point 16, andcontinues longitudinally through a portion of the tube wall. The cutline 14 is coincident with a radius of tube 10 and therefore passingthrough the center 12. This results in cut 18, which is shown in FIG.1B. The tube 10 is then rotated counterclockwise and a second, identicalcut 20 is made, as shown in FIG. 1C, to yield arm 22. The process isrepeated to yield as many arms as desired; generally, the entire centralregion, longitudinally, of the cannula is cut to form a plurality ofarms with spaces in between, as will be described below.

As shown in FIG. 1D, the cutting scheme described above and shown inFIGS. 1A-1C yields a cut which has an angle 28 the measure of which isapproximately or exactly 90 degrees when taken with respect to a line30, which is drawn between the innermost points of the edges of the cut(cut 18 is shown, but this explanation also applies to cut 20.) When anexemplary device comprising four arms 22 a/22 b/22 c/22 d is constructedin such fashion, as is shown in FIG. 1E, the result is the generation offour clockwise blades 60 a/60 b/60 c/60 d and four counterclockwiseblades 50 a/50 b/50 c/50 d. Because all cuts have been made in the samefashion, all of the clockwise blades 60 and counterclockwise blades 50have substantially the same sharpness, leading to a device that will cutuniformly regardless of whether the cutting element comprising theblades is rotated clockwise or counterclockwise.

In some cases, a device of this construction is suitable for theprocessing and treatment of an intravascular structure, such as anatherosclerotic plaque or a thrombus. However, because the face of theblade presented to the lesion during the removal process is asubstantially flat face without a pronounced point, treatment may belimited in some cases to simple maceration of material rather than cleancutting. This may make removal of hardened material difficult orimpossible, and may lengthen the treatment procedure.

A device 110, which is a cutting element for a rotary tool, isconstructed in accordance with the principles of the present disclosureis illustrated in FIG. 2 . Tube 111 has an outer surface 119 and innersurface 121, with a lumen 113 formed therethrough. The tube 111, andtherefore the device 110, defines a longitudinal axis A, about which itis disposed. The device 110 extends from a first end 115 to a second end117. The device 110 may further be subdivided into a first tubularportion 130, a second tubular portion 140, and a plurality of arms 122attached to first tubular portion 130 and second tubular portion 140 andpositioned therebetween.

The arms 122 are preferably of identical length L, which is defined bythe distance between the first end 124 of the arm and the second end 126of the arm 122. As shown in FIG. 2 , the length L of the arms of thetube 111 is at what can be considered a longest length, wherein the tube111 is substantially wholly cylindrical, and the arms 122 have not beenbowed out radially away from the longitudinal axis A.

The length L of each arm 122 is preferably equal to the length L ofevery other arm 122 in order to provide a device 110 in which the arms122 can be bent out of the device 110 to their final configuration inorder to provide a consistent radius of curvature for the arms at theirfunctional, cutting portions. The first ends 124 of the arms 122, insuch an embodiment, align circumferentially at boundary 132, which alongwith first end 115 of the device 110, bound the first tubular portion130 of the device 110. Likewise, the second ends 126 of the arms 122align along at boundary 142 around the circumference of the tube 111,and along with second end 117 of tube 111 (and device 110) provide thebounds of the second tubular portion 140.

The arms 122 are provided by making two cuts through the outer surface119 of the tube 111 and extending through the inner surface 121 of thetube 111, in this case first cut 118 and second cut 120. Preferably, aplurality of cuts are made at consistent intervals about thecircumference of the device 110 such that the entire middle portion ofthe device (that is, the portion between first tubular portion 130 andsecond tubular portion 140) is made of a plurality of arms 122 withsubstantially the same characteristics as one another.

Turning to FIG. 3A, one example of a way of making the plurality of cutsin order to generate a plurality of arms for a device is illustrated. Adevice 210 is made by cutting tube 211 off-center. The tube 211 has acenter 212, and a laser 214 (or other cutting too) is used to make a cutparallel to the radius r of the tube 211, a distance d away from saidradius r. The resultant cut 218 may be seen in FIG. 3B. The cut 218passes through the outer surface 216 of the tube and to the innersurface 213 of the tube 211, giving rise to the first cut 218. The tubeis then rotated as shown in FIG. 3C and a similar second cut 220 ismade, thus creating arm 222 out of the material of tube 211.

As can be seen in FIGS. 3D and 3E, the result of making such anoff-center cut is the generation of an arm 222 that has two differenttypes of blades 250 and 260 with varying sharpness. The off-center cutleads to a pair of angles 228 and 232 which, when measured relative to astraight line 230 drawn between the corners of the cut along the innersurface 213 of the tube, do not have the same measure. As illustrated,angle 228 is obtuse, and angle 232 is acute. The cut 220, made in thesame way, ensures that the next arm will have similar properties. Theblade 250, in which the obtuse angle is internal to the arm 222, will bea sharper blade than blade 260, in which the acute angle is internal tothe arm 222. By making such cuts about the entire circumference of thetube 211 at consistent distances thereabout, a plurality of arms 222with sharp blades 250 a, 250 b, 250 c, 250 d and duller blades 260 a,260 b, 260 c, and 260 d will be generated. As illustrated, the sharperblades will be the tissue-contacting blades when the device is rotatedcounterclockwise, and the duller blades will contact the tissue when thedevice is rotated clockwise.

FIGS. 4A-4E illustrate a different method of making a device 310according to the principles of the present disclosure. Rather thanmaking cuts through the tube 311 parallel to a radius r as in FIG. 3 ,the device 310 of FIG. 4 is made by making a cut along cut line 314through a point 316 on the outer surface and a second point 313 on theinner surface of the tube 311. The cut line 314 forms an angle 328between the radius r which would, if continued, extend through thecontact point 316, which does not have a measure of 0 degrees, or 90degrees, or 180 degrees. Such a cut line 314 may be contained in a planewhich is out-of-plane with the longitudinal axis A in some embodiments.The first cut 318 can be seen in FIG. 4B. A second cut 320 is made,circumferentially displaced from the first cut 318, and defining arm 322therebetween, as shown in FIG. 4C.

As illustrated in FIG. 4D, the cut 318 (or 320) defines a pair of angles338 and 336 internal to the arm 322 on either side of the cut. For thepurposes of illustration, first angle 336 is an obtuse angle, and secondangle 338 is an acute angle. Thus, the side of the arm 322 containingthe obtuse first angle 336 forms a sharp blade 350 and the side of thearm 322 containing the acute second angle 338 defines a dull blade 360.The blades of a four-armed device are illustrated in FIG. 4E.

FIG. 5 is a depiction of a device 410 in accordance with the principlesof the present disclosure shown in an expanded state, as it would bedeployed to the lumen of a body vessel for use. In the expanded state,the arms 422 a/b/c/d are extended radially away from the longitudinalaxis A defined through the tube 411 (or the device 410). The device 410can be said to have the shape of a malecot device. The device 410extends from first end 415 to second end 417. The plurality of arms 422are attached to, and disposed between, first tubular portion 430 andsecond tubular portion 440, and define a plurality of relatively sharpblades 450 and relatively dull blades 460. When the device 410 isrotated in a counterclockwise direction 470, the sharp blades 450 engagethe obstruction or material to be treated; when rotated in clockwisedirection 480, the duller blades 460 are instead the working surface ofthe device 410, and engage the obstruction to be removed.

FIG. 5A shows a cross-sectional view of an arm 422 of the device 410 ofFIG. 5 . Arm 422 has an inner surface 413 and an outer surface 421, withedges 442 and 444 bounding the sides of the arm 422 in a radialdimension. The edge 442 doubles as blade 450, and the edge 444 doublesas blade 460. A device constructed in accordance with the principles ofthe disclosed embodiments has blades that are formed in a radialdimension, in that they proceed from the outer surface 421 to the innersurface 413, and in doing so, the distance from the center of the tube411 is decreased. The arms 422 of the present disclosure are also, in acollapsed configuration of the device 410 (wherein the arms 422 arecompressed into the tube 411 so as to form a cohesive, cylindrical outersurface 413 of said tube), in some embodiments made substantiallyparallel to the longitudinal axis A. In other embodiments, the arms maybe differently constructed, but are non-helical elements of the device.

The precursor tube of any embodiment of the present disclosure may bemade of any suitable material. For embodiments in which tissue is to beexcised or macerated, one suitable material may comprise a metal whichis biocompatible. In some cases, the metal may be an alloy such assurgical stainless steel or the like. In other embodiments, the metalmay be a shape memory metal. A shape memory metal may be advantageouslyemployed in order to facilitate a transition from an expanded state(with blades exposed) to a contracted or collapsed state (with bladespulled radially even with the remainder of the tube). Examples of shapememory metals include, but are not limited to, nickel/titanium alloys,cobalt/chromium alloys, and nickel/chromium alloys.

The device illustrated in FIG. 5 shows a device 410 having four arms 422a/422 b/422 c/422 d. It will be appreciated that a device with anynumber of arms, including three, five, six, eight, ten, twelve, and soforth, may be made without departing from the spirit of the presentdisclosure. It will be understood by a person of ordinary skill in theart that any of the blade cutting schemes disclosed herein could be usedto make such a device.

In some embodiments, based for example on the device 410 illustrated inFIG. 5 , the arms 422 a/b/c/d may have different characteristics fromone another. For instance, the arm 422 a may bear a sharper blade thandoes arm 422 b. In one example, the arm 422 c may have a similar bladesharpness to that of 422 a, and arm 422 b may have a similar bladesharpness to arm 422 d, such that when the device 410 is rotated, asharp blade encounters the thrombus, then a dull blade, then a sharpblade in alternating fashion. The number of arms and sharpnesscharacteristics of such arms may be tailored to the type of thrombus thedevice is expected to encounter.

Further embodiments of methods of cutting a tube or cannula to yield acutting device are shown in FIGS. 6A-6C. Like the blade-bearing arms ofembodiments described previously, the arms 522 and 622 as shown in FIGS.6B and 6C are created by making two cuts through the outer and innersurfaces of the tube. Contrary to previous embodiments, however, the cutlines 518 and 520 intersect at the inner surface 513 of the tube 511,thereby causing the bottom surface of the arm 522 to effectively be asingle straight line. The cut lines 518 and 520 intersect to form anangle 528. The cut lines 518 and 520 may approach the tube 511 fromdifferent angles, leading to a different sharpness of the blade 550a/b/c/d from that of blade 560 a/b/c/d. Similarly, the cut lines thatform the arms 622 a/b/c/d of the device of FIG. 6C intersect, but at theouter surface 621 of the tube 611 rather than at the inner surface.

FIG. 7 illustrates a further embodiment of the device constructed inaccordance with the principles of the present disclosure. In this case,four cuts 772/774/770/776, rather than two, are made in the tube 711 toyield arm 722, which has blade 781 located at the intersection of cuts770 and 772, and blade 783 located at the intersection of cuts 774 and776. Blade 781 is a leading edge located between faces 780 and 782, andblade 783 is a leading edge located between faces 784 and 786,respectively, on opposite sides circumferentially of faceted blade arm722. The blades 781/783 are located radially inward relative to theouter surface 713 of the tube 711, thereby allowing a first point ofcontact with the tissue to be cut which in turn is positioned inwardrelative to the wall of the vessel in which the rotary blade is to beintroduced. Each of cuts 770/772/774/776 may be made at a differentangle relative to the outer surface 713 of tube 711, allowing for blades781/783 to be located at different positions relative to the center ofthe device 710, and to have differing sharpness.

In another embodiment, the cuts made in the tube need not be linear, andcan give rise to an alternatively-shaped blade. As shown in FIG. 8 , anon-linear cut 818 is made in tube 811. The profile of the cut is suchthat it contains a substantially linear portion 890, an arc 892, and asecond substantially linear portion 894. When parallel cuts are madealong the circumference of tube 811, the result is a bladed device 810which has similarly-shaped arms that are effective to cut and maceratetissue similar to other embodiments of the device as disclosed herein.

In addition to making non-linear cuts 818 through the surface of a tube811, the incident angle of the laser may be changed in this embodimentalong the length of the non-linear cut 818. This allows for regions ofgreater or less sharpness along the length of the arm 822. In anotherembodiment, the incident angle may be held constant at a first angle forthe first cut that forms the arm 822, and held constant at a secondangle for the second cut, in order to generate two blades with differingsharpness on the same arm 822.

In another embodiment, as illustrated in FIGS. 9A-9E, a tubular body 911may be cut by a laser 950 using a method that results in areas ofvarying sharpness along an edge of the resultant arm 922. In thisembodiment, the laser cut may be a substantially straight (that is,parallel to the longitudinal axis which runs through the tubular body911) as it originates at boundary 932 and passes through the outersurface 919 of the tubular body 911. However, the angle of approach ofthe laser 950 may be altered long the length of the cut 918, thusresulting in a plurality of zones of varying sharpness. As shown in FIG.9A, the beam 952 of laser 950 cuts the tubular body 911 at a firstangle, resulting in a cut as shown in FIG. 9B with first acute angle 936a and first obtuse angle 938 a. The laser may then be rotated about thetubular body 911 as the cut 918 advances toward boundary 942 at a secondangle as shown in FIG. 9C, resulting in a portion of the arm 922 shownin FIG. 9D having an acute angle 936 b having a different measure fromthe acute angle 936 a, and a corresponding obtuse angle 938 b having adifferent measure from angle 938 a. In another embodiment, the cut 918may result in a blade portion having a right angle portion.

An example of an arm 922 resulting from a cutting regimen as describedabove is shown in isolation in FIG. 9E. At first end 924, the blade ofarm 922 makes a first inner angle 960, and at second end 926, the bladehas a second inner angle 962 different from first inner angle 960. Insome embodiments, the inner angle along the blade may change multipletimes. In other embodiments, the center of the arm 922, where thediameter is greatest and there is a chance of contacting the vesselwall, may be constructed as a back bevel in order to minimize trauma.

A cutting device with arms 922 having a variety of blade regions ofvarying sharpness. Such a structure may be suitable for excising aheterogeneous thrombus, which may have firm portions, gel-like andliquid portions, and may be best treated by exposure to a cutting toolhaving a variety of regions of sharpness.

A cutting device of the present disclosure may be operably attached to arotary tool, preferably one which includes a motor capable of rotatingthe bladed device in both a clockwise and a counterclockwise direction.The rotary tool may be coupled to a handle which allows a user tomanipulate the device once it has been delivered to an intravascularsite to be treated. The handle may include means of modulating the modeof operation of the device, such as a thumbswitch. The thumbswitch isable to change the device from an off condition, to one in whichrotation in the clockwise direction is facilitated, to one in whichrotation in the counterclockwise direction is facilitated. The assemblymay also include a delivery sheath which contains the cutting portion ofthe device. When the cutting portion is inside the delivery sheath, ittakes on its collapsed position. When it is pushed out of the sheath, orthe sheath is retracted proximally toward the practitioner, the armsadopt their radially expanded configuration, thereby enabling rotationalcutting and/or maceration of tissue.

As a person skilled in the art will readily appreciate, the abovedescription is only meant as an illustration of implementation of theprinciples this application. This description is not intended to limitthe scope of this application in that the system is susceptible tomodification, variation and change, without departing from the spirit ofthis application, as defined in the following claims.

1-21. (canceled)
 22. A method for disrupting material in a body vessel,the method comprising: delivering a medical device comprising a bodyhaving a first blade having a first sharpness and a second blade havinga second sharpness, wherein the first sharpness is different than thesecond sharpness; rotating the body in a first circumferential directionsuch that first blade disrupts material in the body; and rotating thebody in a second circumferential direction, which opposes the firstcircumferential direction, such that the second blade disrupts materialin the body by contacting the material at a different angle compared tothe first blade.
 23. The method of claim 22, wherein the body comprisesat least one arm, wherein the at least one arm comprises the first bladeand the second blade.
 24. The method of claim 23, wherein the firstblade is disposed along the at least one arm at a location opposite thesecond blade.
 25. The method of claim 23, wherein the first blade has anobtuse angle internal to the at least one arm, and the second blade hasan acute angle internal to the at least one arm.
 26. The method of claim23, wherein the body comprises a first tubular portion, a second tubularportion spaced axially apart from the first tubular portion, and aplurality of arms extending between the first tubular portion and thesecond tubular portion, wherein the at least one arm having the firstand second blades is among one of the plurality of arms.
 27. The methodof claim 26, wherein each of the plurality of arms comprises anidentical design to the at least one arm having the first and secondblades comprising the respective first and second sharpness, the methodfurther comprising using each of the plurality of arms to disruptmaterial using their respective first blades when rotating the body inthe first circumferential direction; and using each of the plurality ofarms to disrupt material using their respective second blades whenrotating the body in the second circumferential direction.
 28. Themethod of claim 22, wherein the body comprises a malecot.
 29. A methodfor disrupting material in a body vessel, the method comprising:delivering a medical device comprising a body comprising an innersurface and an outer surface, extending from a first end to a second endand defining a longitudinal axis therethrough, and wherein the bodycomprises a first blade and a second blade; rotating the body in a firstcircumferential direction such that first blade disrupts material in thebody; and rotating the body in a second circumferential direction, whichopposes the first circumferential direction, such that the second bladedisrupts material in the body, wherein at least one of the first bladeand the second blade is oriented in a plane that does not intersect withthe longitudinal axis.
 30. The method of claim 29, wherein the firstblade comprises a first sharpness that is different than a secondsharpness of the second blade.
 31. The method of claim 29, wherein thebody comprises at least one arm, wherein the at least one arm comprisesthe first blade and the second blade.
 32. The method of claim 31,wherein the first blade has an obtuse angle internal to the at least onearm, and the second blade has an acute angle internal to the at leastone arm.
 33. A method of making a medical device for disrupting materialin a body vessel, the method comprising: making a first cut in a tubularbody, the tubular body comprising an inner surface and an outer surfaceand extending from a first end to a second end and defining alongitudinal axis therethrough, the first cut originating between thefirst end and the second end and terminating between the first end andthe second end; making a second cut in the tubular body offset from thefirst cut to define a first arm between the first and second cuts, thesecond cut originating between the first end and the second end andterminating between the first end and the second end; wherein the firstarm comprises a first blade defined by the first cut and having a firstsharpness, and a second blade defined by the second cut and having asecond sharpness; wherein at least one of the first cut and the secondcut is made in a plane which does not intersect the longitudinal axis.34. The method of claim 33, wherein the first sharpness is differentthan the second sharpness.
 35. The method of claim 33, wherein aplurality of first cuts and a plurality of second cuts are made in thetubular body, thereby defining a plurality of arms between each firstcut and its corresponding second cut.
 36. The method of claim 35,wherein the plurality of arms each comprises a first blade in the samerelative orientation in a circumferential direction.
 37. The method ofclaim 35, further comprising displacing a portion of each of theplurality of arms radially outward.
 38. The method of claim 33, whereinthe first cut and the second cut intersect at the inner surface of thetubular body.
 39. The method of claim 33, wherein the first cut is madeat a first angle relative to the outer surface of the tubular body, andthe second cut is made at a second angle different from the first angle.40. The method of claim 33, wherein each of the first cut and the secondcut are formed by a laser.
 41. The method of claim 40, wherein the firstcut is formed with the laser oriented at two or more different anglesrelative to the tubular body along a length of the first cut.